Overview

Mapping of compiled Waze events for all of 2018 in Bellevue, WA. Events within 6 miles of the center of Bellevue were included in this initial work, and the ‘city’ field in the Waze data was used to remove events where were labeled as being outside of Bellevue. One of the next steps will be to clip to the city boundary shapefile. In addition, the Bellevue road network has not yet been incorporated in these maps. A base layer derived from Open Street Maps is used for these maps.

## WA_2018-01.RData 
## WA_2018-02.RData 
## WA_2018-03.RData 
## WA_2018-04.RData 
## WA_2018-05.RData 
## WA_2018-06.RData 
## WA_2018-07.RData 
## WA_2018-08.RData 
## WA_2018-09.RData 
## WA_2018-10.RData 
## WA_2018-11.RData 
## WA_2018-12.RData

First, looking at frequency of all Waze incident reports by street name. Of all 297,280 Waze incident reports, 16,453 (5.53%) had no value provided for ‘street’ in the data. Of the 8,145 crash reports, 1,247 (0.42%) had no value provided for ‘street’.

Ten most frequent street names for all Waze incident reports in study period
Street Frequency
I-405 S 62,381
I-405 N 33,002
I-90 W 30,317
I-90 E 18,949
SR-520 W 17,234
W Lake Sammamish Pkwy SE 6,837
I-405 N Exp Toll Ln 6,754
I-405 S Exp Toll Ln 5,597
SR-520 E 5,285
Coal Creek Pkwy SE 5,050

In the Waze data, there are two ways to make an initial filter to omit roads which are not in the jurisdiction of Bellevue: to filter by street names, and also to filter by road class. Waze uses their own road classification system; interstates are all class ‘3’ in the Waze system.

Here we filter the Waze data by excluding I-405, I-90, as well as SR-520 (assuming this is not in Bellevue jurisdiction), and by omitting any additional events on class 3 roads. Filtering by name effectively removes nearly all class 3 roads. Some Waze events missing a street name and with an incorrect road class may still appear on the interstates after this filtering process; a GIS approach to snap Waze events to road segments will also be necessary.

Ten most frequent street names for all Waze incident reports, omitting highways, in study period
Street Frequency
W Lake Sammamish Pkwy SE 6,432
Coal Creek Pkwy SE 4,935
to I-405 N / Everett 4,512
Bellevue Way SE 4,245
148th Ave NE 3,754
148th Ave SE 3,430
to I-405 S / Renton 3,355
NE 8th St 2,842
Richards Rd 2,197
140th Ave NE 2,021

The Waze incidents remaining after filtering out highway events are summarized in the table below by alert type and subtype. Not all alerts have a subtype provided.

Heat maps

The following heat maps show 2-D kernel density estimates of incident frequency. Warm colors indicate high frequency, cool colors show lower frequency. Maps are shown with and without individual incidents plotted for clarity.

All Waze crash reports

8,145 Waze crash reports.

Waze crash reports, omitting highways

2,255 Waze crash reports, after filtering out highways.